The affidavit details a witness' account that Javier Edgardo Castillo was riding in a sport utility vehicle when he pulled out a handgun, pointed it out the driver's-side rear window and fired twice.

Castillo was arrested Tuesday and accused of the Nov. 12 shooting death of Laronia Fay Bowers, 51, and the wounding of Edward Mincy, 59.

Castillo was taken to the Hillsborough County Juvenile Assessment Center and faces charges of second-degree murder and attempted second-degree murder.

Another purported passenger in the SUV, 18-year-old Abel Cruz Dimas of Lakeland, already had been arrested in connection with the shooting. He, too, was charged with second-degree murder and attempted second-degree murder.

Nearly a month after the killing, the arrest of Castillo came after results from a state ballistics report pointed to him as the probable shooter, said Plant City police spokesman Tray Towles.

The day of the shooting, police stopped the maroon Chevrolet SUV because the driver wasn't wearing a seat belt, the arrest affidavit said. Witnesses identified the vehicle as the one that left the fatal scene, and one witness recalled seeing gunfire from the SUV.

Plant City police detectives said they searched the vehicle and recovered a .357-caliber Western Derringer, loaded with two rounds, from under the driver's seat.

Castillo's fingerprints, the affidavit said, were found on the rounds.

Police say they also discovered one spent shell and several other live rounds in the vehicle. The arrest affidavit indicates the handgun and ammunition may be of the same caliber as the bullets that hit the victims.

Affidavits list Castillo as a Plant City High student, and both Dimas and Castillo are identified as members of the national gang Sur-13. But police spokesman Towles said the shooting did not appear to be gang-related or linked to gang retaliation.

Investigators also have said the shooting did not appear to be a random attack, but another affidavit in the investigation indicates Bowers and Mincy may not have been the intended victims.

Tuesday's arrest of Castillo will likely not affect the charges against Dimas, who was arrested Nov. 12, Towles said. But he added that evidence points to Castillo as the only gunman.

The investigation is ongoing.

Stephanie Wang can be reached at swang@tampabay.com or (813) 661-2443.